Comparison of Dermoscopy and Wood's Lamp in the Assessment of Stability of Vitiligo.

Background: The stability of vitiligo is mainly assessed using clinical criteria. Wood's lamp and dermoscopy have been proposed as valuable alternatives.

Objective: The objective of the study was to compare the utility of dermoscopy and Wood's lamp examination in the assessment of stability in vitiligo compared with clinical criteria and to define the best cutoff score using BPLeFoSK criteria in determining vitiligo stability.

Patients and methods: The study was conducted among patients with vitiligo attending a tertiary care center. The study design was a diagnostic test evaluation. One hundred and ten patients with vitiligo were recruited over 18 months. The most recent lesion in each patient was assessed for its stability using the clinical evaluation, Vitiligo Disease Activity (VIDA) score, Wood's lamp, and dermoscopy with the BPLeFoSK score, where a score ≥1.5 indicated stable vitiligo.

Results: The study revealed moderate agreement between Wood's lamp and dermoscopy (κ=0.55) and a fair agreement between clinical evaluation and both Wood's lamp (κ=0.33) and dermoscopy (κ=0.40). Wood's lamp showed 72.3% sensitivity and 66.7% specificity, while dermoscopy had 74.1% sensitivity and 73.5% specificity. Wood's lamp had 87% accuracy in identifying stable vitiligo but only 43.9% accuracy in ruling it out compared to clinical criteria. Dermoscopy demonstrated slightly higher effectiveness. The area under the receiver operating characteristic curve for dermoscopy versus clinical criteria was 0.826, while Wood's lamp scored 0.695. A BPLeFoSK cutoff score of ≥3.5 was specific (97.6%) for identifying stable vitiligo, but sensitivity was low (25.6%).

Limitations: The study's limitations included the cross-sectional study design, examination of only one lesion per patient, lack of blinding, absence of follow-up, absence of histopathologic examination of the lesions, lack of sequential observation through a combination of clinical, dermoscopic, or Wood's lamp examination, and utilization of VIDA scoring system which itself has recall bias. Use of a non-validated scoring system (BPLeFoSK) is also a limitation of this study.

Conclusion: This study shows that dermoscopy and Wood's lamp are equally helpful in clinical assessment. We propose a cutoff score of more than or equal to 3.5 in BPLeFoSK score.